The invention relates to illuminating apparatus for illuminating a face of a driver of a vehicle, to image capturing apparatus for capturing a facial image of the driver by use of the illuminating apparatus, and to monitoring apparatus using the image capturing apparatus. In order to prevent vehicle accidents due to driving errors, driver monitoring apparatus have been proposed that are adapted to capture an image of a face of a driver of a vehicle, particularly of his or her eyes and an area therearound, to monitor based on the captured image whether the driver falls asleep or inattentive, and, upon detection of drowsy or inattentive driving, to perform a countermeasure operation, such as of providing a warning to the driver.
Such driver monitoring apparatus are adapted to analyze a driver's image captured by a camera. Because of directly received outside light, however, a vehicle cabin, in particular a driver seat, generally provides the least ideal conditions for the camera to capture images. At daytime, the driver seat shows extremely high luminance levels due to direct sunlight. At nighttime, in contrast, the driver seat shows extremely low luminance levels due to absence of lighting. In a situation such as where the vehicle passes through a tunnel, in addition, the driver seat shows a random alternation of extremely high and low luminance levels. In order to provide stable conditions for image capturing, i.e., stable luminance, JP 2004-058799A discloses a driver monitoring apparatus that uses infrared radiation to illuminate a driver. More specifically, the apparatus of JP 2004-058799A is adapted to illuminate a driver's face by infrared radiation that is emitted by an infrared light emitting element and reflected by a cold filter. The infrared light emitting element is disposed on a dashboad and out of the driver's line of vision. The cold filter is formed on a surface of instrument panel.
However, the prior art apparatus has the following problems.
(1) The prior art apparatus has an illuminating apparatus fixedly mounted. Drivers have different eye levels depending on their physical constitution. A driver has different eye levels depending on his or her positions, driver seat adjustments, etc. Accordingly, the illuminating apparatus is required to illuminate a wide area in order to illuminate eyes of a driver, with any physical constitution and in any position, seated in a driver seat in any adjustment position. Therefore, the light emitting element is required to have a high luminance. The prior art apparatus is thus disadvantageous in difficulty in downsizing the illuminating apparatus, and in high power consumption and manufacturing costs.
(2) The prior art apparatus has the illuminating apparatus disposed in front of a driver in order to illuminate his or her face. However, a number of essential instruments and gauges are also provided in front of the driver. The prior art apparatus is thus disadvantageous in that interior design of the vehicle causes the illuminating apparatus to be disposed at a limited location.
In light of the foregoing problems, a feature of the invention is to provide a driver illuminating apparatus that is adapted to illuminate a face, in particular eyes and an area therearound, of a driver of a vehicle; a driver image capturing apparatus employing the illuminating apparatus, adapted to capture an image of the driver for facilitated facial recognition; and a driver monitoring apparatus employing the image capturing apparatus.